High hopes for hemp in Australian building industry

The builders of an award-winning home made from hemp hope to inspire a shift towards making it a mainstream construction material.

Balanced Earth recently won the Master Builders New South Wales Energy Efficient Building award for a home in the Byron Bay hinterland, in northern New South Wales.

Architect Michael Leung said while industrial hemp was popular in textiles, there was a growing interest in using the cannabis sativa plant in buildings.

“I think we’ve just hit the hemp industry at the right time, and in Byron Bay there’s a real consciousness and responsibility to the environment so it’s just seamlessly flowed together,” he said.

Builder Luke Wrencher said hemp’s most positive attribute was its sustainability.

“When you grow the hemp it takes the carbon out of the atmosphere and it stores the carbon in that fibre and you process it and lock the carbon up into the building, so at that point it becomes carbon negative,” he said.

“To have a building material that is carbon negative is almost revolutionary.”

Making hempcrete

To use hemp in construction, the builders take the chopped hurd, that is the inner woody core, and mix it with lime and sand to create a substance they have dubbed “hempcrete”.

In the award-winning Byron hinterland home, the builders constructed frames from recycled timber to hold the hempcrete walls.

“The actual packing of the hemp is very easy to do, kids, children, wives, husbands, anyone can do it,” Mr Wrencher said.

“The hardest thing is you need a carpenter for your formwork, but then it can definitely be a community thing to do, pack the hemp into the formed up walls.”